Case IH 627-04 - ITBV – ITBV: 12V supply voltage low

The control module is not receiving sufficient operating voltage to function correctly, which can compromise the operation of the Intelligent Trailer Brake Valve (ITBV).

• MAGNUM AFS Connect
• Magnum 250
• Magnum 280
• Magnum 310
• Magnum 340
• Magnum 325 PowerDrive
• Puma 150
• Puma 200 CVX
• Maxxum 145 Multicontroller
• Farmall

1. 1

   Verify system voltage from the battery and alternator is above 10.5 VDC to rule out base power issues.

2. 2

   Inspect the ITBV electrical connectors (such as the X-386F dust cap/connector area) for corrosion, moisture, or backed-out pins.

3. 3

   Test the delayed power circuit (cc# 006) for continuity, looking for open circuits, chafed wires causing a short to ground, or high resistance.

4. 4

   Check the relay panel and all fuses supplying power to the ITBV and Armrest Control Unit.

1. 1

   Resolve Power Supply Issues

   If the battery or alternator is faulty, replace them to restore proper base voltage to the tractor.

2. 2

   Repair Wiring

   If the diagnostic checks reveal a short or break in the delayed power circuit (cc# 006), splice and repair the damaged section of the wiring harness or replace the affected connector terminals.

3. 3

   Module Reset

   Disconnect the Armrest Control Unit/ECU connectors (e.g., X653 and X654) and reconnect them to reset the connection.

4. 4

   Replace the ITBV

   If the power supply is verified at the valve connector (above 10.5V) but the fault persists, the ITBV solenoid/valve assembly has likely failed internally and must be replaced.

5. 5

   Clear Codes and Calibrate

   After replacing the valve or repairing the wiring, clear the fault codes using an Electronic Service Tool (EST) and perform a test drive to ensure the trailer brakes engage properly without throwing a low-voltage error.